Assessment of contribution of EHD to the cooling of power semiconductor devices immersed in dielectric liquids

Abstract

International audienceThis paper presents an experimental study of EHD heat transfer enhancement in dielectric liquids, and an evaluation of its contribution to cooling of power electronic components. Heat transfer measurements are carried out in a vertical coaxial electrode system filled with benzyltoluene liquids. The influence of voltage wave shape (AC, DC, impulses), frequency, and liquid viscosity on heat transfer enhancement are measured. The optimal heat transfer occurs for a specific frequency with ac and impulse voltages, and liquids of lower viscosity. Unfortunately, in a typical power electronics module geometry (power diode on a ceramic substrate), almost no improvement of the diode cooling is recorded when this structure is filled with a liquid